Vulnerability Assessment Of Urban Water Distribution Network(VAUWDN) Based On Network Graph Topology Analysis

Water resources are the basic material for human production activities and the basic guarantee for the sustainable development of the national economy.In the face of urban water shortage,serious water pollution,and urban water shortage,water saving and improving water efficiency are effective measures for water resources sustainability.The water distribution network is a key member of the urban water supply system.It’s layout is more and more complicated with the development of urban construction and the expansion of urban land use,and the difficulty of planning,designing and operating management of urban pipe network system also increases.The mismatch between the development of the network scale and its ability to prevent and mitigate disasters is the main problem faced by current design managers of pipe network systems.Vulnerability assessment is an important technical means to identify key nodes of the pipeline network,formulate efficient management methods,and improve the safety and economy of pipeline network operation.This paper first defined the main ideas of vulnerability assessment.The concept of network vulnerability was proposed based on the existing vulnerability research.Then,according to the impact of the network network accident,the vulnerability of the network was divided into direct and indirect vulnerability,and used the direct vulnerability as the main object of the research.Subsequently,the analytic hierarchy process and indicator function method were used to divide the vulnerability of the network into hydraulic and water quality vulnerability,the main influencing factors were analyzed,and screened the factors to establish the hydraulic and water quality vulnerability assessment models.Finally,the model was applied to the Chongqing Yuelai Eco-city reclaimed water distribution network.An economic comparison model based on the hydraulic vulnerability control scheme was also established to screen economic and technical solutions for controlling the system’s hydraulic vulnerability.The main conclusion as below:The process of vulnerability assessment and application includes four stages,vulnerability identification,vulnerability model establishment,vulnerability assessment and application,and it’s the basic attribute of the system.Its existence is accompanied by the formation of the network and will exist for a long time until the network is removed.It can shown by the degree of damage to the water supply performance of the system and the subsequent socio-economic,due to the internal factors such as the unstable water pressure,internal corrosion,or external load,under maximum operating conditions.The factors affecting the hydraulic vulnerability include the connectivity of the pipe network topology and the hydraulic characteristics.The vulnerability assessment model can be divided into the hydraulic vulnerability of the pipeline and the system.In the range of 20% change of each index,hydraulic vulnerability is the most sensitive to the segmental freedom index.If out of range,the model is most sensitive to the accident vulnerability index.The influencing factors affecting the water quality vulnerability of the pipeline network mainly include residual chlorine,water age and topological position.Water quality vulnerability is based on hydraulic vulnerability.The pipe network system consists of pipeline and node elements.The water quality vulnerability assessment model can be divided into pipeline and system water quality vulnerability assessment models.The flow rate of the pipeline of the eco-city reclaimed distribution network system is generally low,and the piplines above the moderately vulnerability level account for 26.67%,and most of them are close to the reclaimed water source or the midway pressurized pumping station.The position of the pipe topology has a great influence on the vulnerability level of the pipeline.The comprehensive hydraulic vulnerability index value of the pipe network system is R=2.027.The water quality vulnerability index of the pipe network is 2.423,and the water quality vulnerability level of the pipe section is mainly moderately vulnerability,accounting for 81.26%.The pipe network can ensure the stability of water quality.With high vulnerability is located at the edge of the pipe network which has a small flow rate and large water age.In the operation management,the area should pay attention to and take appropriate water quality control measures.The system vulnerability indicator value is 2.126.Through research,a set of quantitative analysis models suitable for vulnerability assessment of urban water distribution network were proposed.The model can provide reference for the management department to conduct network performance and risk management,and provide research methods and theoretical basis for the optimization design work of drainage design planners,which has certain theoretical significance and practical meanning.